Wireless receiving cabinet



Jan. 10, 1928.

F. CONR AD WIRELESS RECEIVING CABINET 5 Sheets-Sheet 1 Filed April 18, 1922 INVENTOR flank Conrad BY aWiTI NESSES:

ATTORNEY Jan. 10, 1928. 1,655,985

F. CONRAD WIRELESS RECEIVING CABINET Filed April 18, 1922 5 Sheets- Sheet 5 INVENTOR /50 Frank Con/dd /'/48 BY A'TTORNEY adapted to co Patented Jan. 10, 1928.

UNITED, STATES FRANK CONRAD, OI PITTSBURGH,

ELECTRIC & KANUI'AOTUBING PATENT OFFICE.

wmnnnss nncmvina canmnr.

Application fled April 18, 1922. Serial No. 555,215.

My invention relates to wireless telegraph circuits and apparatus and more es ecially to cabinets adapted to embody wire ess receiving systems.

5 In its broad aspect, the princlpal ob ect of my invention is to provide a umta structure, as, forinstance, a cabinet, wine .is of simple, compact and rugged deslgn, yet-pleasing in appearance, and wh1ch 1s ntain, a complete wireless receiving system, together with a loud-speak ing device therefor.

More specifically, another object of my 1nvention is to dispose the customary wireless receiving apparatus in a cabinet in such manner that the various parts and circuit terminals therefor are readily accessible at all times.

Other objects of my invention will appear more fully from the following description of the nature, mode of operation and constructional details thereof.

According'to my invention, I provide a cabinet comprising a chamber having a let ticed opening in one wall and an antenna and battery terminal connectors in an opposite wall thereof. A lid for said chamber may be hinged to the latter wall. A hollow cover is provided for said lid in order to ob tain a closed space immediately above the lid.

In one form of structure embodying my invention, the cover is hinged to the edge of said lid. In a preferred structure, however,

the cover is hinged to the same wall as the lid. The cover and lid may be maintained in elevated positions by means of latches of suitable design. A sound-amplifying device, as, for instance, a horn, is so disposed in said chamber that the large end of said hornfaces said latticed portion. -Wave-respon sive apparatus, such as is usually associated with a wireless receiving system, is supported from'the under side of said hinged lid in any approved manner.

My invention further consists in the constructional details and arrangements hereinafter described and claimed and shown in the accompanying drawing, wherein Figure 1 is a diagrammatic view of circuits and apparatus embodying my invention; v Fig. 2 is a side elevational view, shown partially in section on the line IIII of Fig. .3, and illustrating a form of cabinet 55.

adapted to contain ratus shown in Fig. 1.

ig. 3 is a to plan view of the structure of Fig. 2 with t e hinged cover removed; Fig. 4 is a front elevational view of the structure shown in the previous figures, with the cover closed, and illustrating the preferred lattice work design;

Figs. 5 and 6 are front and side elevational views, respectively, of a modified cabinet design embodying my'invention;

Fig. 7 is an enlarged fra tional view of the structure s own in Figs. 5 and 6, illustrating the hinge connections of the lid and the cover member to the walls'of the cabinet.

In Fig. 1 is shown one ty e'of receiving circuit, which is adapted to be employed in a receiving cabinet embodyin my invention, said circuit c0mprising,1n general, a'

radio-frequency amplifier tube 1, which is associated with input and output circuits coupled for regenerative action, a resistancecoupled detector tube 2 and a air of cascade-connected resistance-couple quency amplifier tubes 3 and 4.

The radio-frequency amplifying tube 1 comprises an anode 5, a controlling grid .6 and a hot cathode 7,-thelatter having external circuit terminals 8 and 9. The in ut circuit of the radio-frequency amplifying tube 1 extends from the grid 6 to the hotcathode terminal 8 through a conductor 11, stationary and movable coils 12 and 13, respectively, of a variometer 14, a conductor 15, a conducting plate or so-called shield 16 and a conductor 17, which contains a series-connected ballast lamp 18.

The grid end of the stationary coil 12 is connected to one terminal of a wave-changing condenser 19 21. Intermediate sections of said condenser are connected to antenna circuit terminals 22 and 23, respectively, to provide short and long-Wave circuit connections for the receiving system. The filament end of the movable coil 13 is connected to a grounded circuit terminal 24 through the conductor 15, the shield 16 and a conductor 25.

The filament terminal 8 is connected to the shield 16 which is connected to the ground terminal 24, which is also designed to be employed as the negative-terminal conaudio-frethe circuits and appaentary secby means of a conductor nection for a filament-exciting battery (not shown), through the ballast lamp 18, the

shield 16 and the conductor 25. The remaining filament terminal 9 is connected to an adjacent terminal 26, which is designed to be employed as the positive-terminal connection-for said filament battery, through a conductor 27 and'a conductor 28, containing a switch 29. The action of the ballast lamp 18 is to prevent the current supplied to the filament 7 from increasing beyond a predetermined value.

The output circuit for the am lifier tube 1 extends from the plate 5 to t e filament terminal 9 through a-conductor 31, a feedback coil 32, having an adjustable tap connection 33, a conductor 34, a resistorcoupling device 35, a conductor 36, which connects the remaining terminal of said device to a positive terminal of a source of high-potential energy 37 said source of energy 37 aconductor 38, the switch 29 and the conductor 27. A condenser 39 is included in a circuit extending from the plate side of the resistor to the filament 7 to provide a shunt path of low impedance around the resistor 35 and the plate battery 37 for currents of radio frequency.

The detector tube 2 com rises an node 41, agrid 42 and hot cathode 43, terminals 44 and 45 of the latter being connected, by conductors 46 and 47 respectively, in parallel relation to the filament supply connections 16 and 27 of the tube 1. A ballast lamp 48 is included in the conductor 46 for reasons hereinbefore mentioned. The grid 42 of the detector tube 2 is connected to the plate side of the resistor 35 by means of a conductor 49 which contains a series-connected biasing condenser 51. The filament 43 of said tube 2, as hereinbefore stated,

being connected in parallel with filament 7 of tube 1, potential variations across said resistor coupling device. 35, incident to currents in the plate circuit of the tube 1, are impressed upon the input or grid-filament elements 42 and 43, respectively, of the detector tube 2. 7

A grid-leak circuit 52 extends from the grid 42 to the filament terminal 44 and contains a resistor 53 having a valve of'the order of a megohm. The anode 41 is connected tot-he filament terminal 45 through i a conductor 54, a series-connected resistancecoupling device 55;the conductor 36, the high-potential source of energy 37 the con-' ductor 38, the switch 29, the conductor 27 and the conductor 47.. Y

The auto-frequency amplifying tube 3 comprises an anode 56, a grid 57 and a filament 58, terminals 59 and 61, one of the latter being connected, by conductors 62 and 63, respectively, in parallel relation'to the filament-Suppl connections 16 and 27 of the tube 1.. ballast-lamp 64 is included connected in the conductor 62 for reasons hereinbefore mentioned. The grid 57 ofthe amplifier tube 3 is connected to the plate side of the resistor 55 through a biasing condenser 65. Since the filament 58 of the tube-3 is connected in parallel relation with the filament of the preceding tube 2, it can be seenthat potential variations acrossresistor 55, incishunt circuit 68, which contains a series-connected condenser 69 and an adjustable choke coil 71, extends from the anode 56 of the amplifier tube 3. to the filament terminal 61. The purpose of the circuit 68 will be explained more fully hereinafter.

The remaining audio-frequency amplifier tube 4 comprises an anode 72, a grid 73 and a filament-74, terminals 75 and 76 of the latter being connected, by conductors 77 and 78, respectively. to the filament-supply connections 16 and 27 of the tube 1. A ballast lamp 79 is included in the conductor 77 for purposes hereinbefore mentioned. The

grid 73 isconnected to the anode side of the resistor 67 through a grid condenser 80. Since the filament 74 of the tube 4 is connected in parallel. to the filament 58 of the preceding tube 3, potential variations across the resistor 67 are impressed upon the gridfilament elements 73 and 74, respectively, of the amplifier tube 4. The anode 72 is to the filament terminal 76 through a translating device shown as a telephone receiver 81, the source of energy 37, the conductor 38, the switch 29 and the conductor 78. A grid-leak device 82 may be included in a circuit 83 which extends from the grid 73 to the filament terminal 75 of the tube 4.

While I have described the several tubes as being energized from an external source phragm (not shown) embodied in the telephone receiver 81. The effectof this circuit is to provide a partial by-pass for energy resonant to the frequency of said diaance with well known principles, it will not I and be further described.

The circuits and apparatus of Fig. 1 may be assembled in a cabinet 84 of preferred design, as shown in Figs. 2, 3 and 4, or in a cabinet 85 of modified design, as shown in Fi e. 5, 6 and 7. Referring to Figs. 2, 3 4, the cabinet there shown comprises a substantially rectangular chamber 86, having walls 86, 87, 88 and 89 and-a. base 91 therefor. The ends of the several walls are extended below the base 91 to provide a space 92 immediately adjacent the lowerside of the base 91. The cabinet is thus supported by the extended portions of the several walls.

The front wall 86 is provided with an opening 93 adapted to receive a removable latticed portion 94 of any suitable design, as indicated in Fig. 4. The antenna binding posts or circuit terminals 22 and 23 are hor-- izontally arranged near the middle of the rear wall 88, while the filament battery terminals 24 and 26 are similarly arranged directly beneath the same. The inner surfaces of the upper ends of the front and rear walls 86' and 88 are provided with shoulders 95 and 96 which serve as supports for a lid 97 which is adapted to cover the chamber 86 and which. is hinged to the rear wall 88 at 97. The depth of'the shoulders is preferably such as to cause the upper surface of the lid 97 to lie just below the upper edges of the several walls.

The lid 97 is composed of suitable insu-.

lating material and has a shield 98 of conducting material disposed on the under surface thereof. As is well known, the effect of such shield is to prevent the capacity effects attendant upon the presence of a persons body from unbalancing the operation of the system. A hollow cover member 99 adapted to form a space 101 immediately above said lid 97 is connected to the rear wall 88 by means of hinged connections 102. The cover 99 may be. secured in an elevated position bymeans of a link 103, one end of which is pivotally mounted. to the cover 9.9 and the other end of which is adapted to engage a latch mechanism 104 of suitable design mounted upon the wall 87, as shown in Figs. 3 and 4.

When the cover 99 is .portion or boss 126,

extend down into the chamber 86, as shown .in Figs. 2 and 4.

closed, the connecting link 103 is caused to A tuning device or so-called variometer 14 is I mounted upon a. cylindrical member 107 which is mounted at a point on the under surface of the lid 97 substantially centrally disposed. The movable element 13 of the variometer 14 is mounted upon a cylindrical member 107'which is adapted to be rotatably supported, from its upper end, by means of.a rod 109 carried by a dial plate 111 which is disposed upon the upper surface of the lid 97. A handle portion 112 is attached to the rod 109, whereby the latter may be more readily turned. A centering rod 113 extends through the lower portions of the two cylindrical members to prevent relative side motion of said members. The feed-back coil 33 is mounted upon the stationary member 107.

A portion of the lid adjacent the rear wall 88 is provided with two parallel rows of perforations 114 and 115 of such size as to admitof the insertion of vacuum tubes 116 or ballast lamps 117 therethrou h. The ballast lamp 117 is of an improved design and comprises an enclosing envelope 118, having a resistor element 119 suitably supported from a press 120 by means of carrier rods 121 and 122. A base for the tube comprises acollar 123, one end of which embraces a lower portion other end of which embraces an block 124 carrying a pair of terminal eontactor pins 125 which may be of circular Cr0ss-section. The pins 125 may be connect ed to the carrier rods 121 and 122 in any approved manner. The outer side of the block 124 may be provided with a raised as indicated in Fig. 2.

A base socket panel 127, having contact portions 128 and 129 adapted to receive the pins of the vacuum tubes 116 and the ballast lamps 117, respectively, is suitably disposed below the perforated portions just mentioned and secured to the under side of the lid 97 by means of strap connections 130.

The contact portions 129, adapted to receive the terminal pins of the ballast lamps 117, are preferably disposed beneath the row of perforations 115 nearest the hinged portion of the lid 97. A pliable material 131, as, for instance, felt, 1s disposed between strap 130 and the panel 127 and serves to provide a resilient mounting for the latter.

. posed in which are secured to the base 91 of the The grid biasing condensers 51, and 80 are suitably mounted on the under side of the socket panel 127 immediately adjacent their corresponding tube contact portions, as indicated in Fig. 3. V

The lid 97 may be provided with an additional perforation 132 substantially centrally disposed between the walls 87 and 89 and just to the rear of the ballast lamp perforations 115. A cylindrical member 133 having a perforated base 134 is mounted on the under'surface of said lid immediately beneath the perforation 132 to provide a receptacle for spare parts, as, for instance, an additional tube.

The antenna-wave-changing condenser 19 may be mounted at a point on the under surface of said lid 97 immediately adjacent the antenna-terminal connectors 22' and 23 and just to one side of the spare-part receptacle 133. The by-pass condenser 39 may be mounted on the under side of said lid at a point substantially midway between the front and rear walls 86 and 88, respectively, and adjacent the wall 89.

The adjustable inductance device 71 and the condenser 69 may the under side of said lid directly opposite the condenser 39 and adjacent the wall 87 The switch 29 is of the-push-button type and is mounted flush with he upper surface of the lid 97 directly opposite the tuning device 14 and adjacent the wall 89. As is standard in such switches, the operation of one push button thereof closes the circuit while the operation of the other opens the same. In order to prevent the switch 29 from being accidentally left closed, when the cover member 99 is down, and the wireless receivin apparatus is not in operation,

a stop member 135 may be disposed upon said cover 99 in such position that, when the cover 99 is closed, the stop 135 automatically engages the proper push button and opens the switch 29.

A metallic amplifying horn 136 of substantially U-shape and having flaring sides is supported on the base 91 of the chamber 86 by means of supporting members 137 and 138, which are cast integral therewith, whereby the smaller end of said horn 139 may lie adjacent to the wall 87. The latter end may be provided with an extension 140 adapted to provide a support for the telephone receiver 81. The large end of the horn may be further extended to the latticed portion 94 by means of an extension 141 which also has flaring sides.

The sources of energy 37 and 37 f the latter being not shown in one corner of the chamber 86, which is bounded by strips 142 and 143 chamber 86. Astrip 144, which is secured at one end by a block 145 and a screw 146 also be mounted on Fig.1, may be dis- 5, 6 and 7 distinguishes from that shown .in Figs. 2, 3 and 4 merely in the specific design thereof, the receiving apparatus being arranged substantially as in the preferred design. In the modified design, it will be noted that the cabinet is provided with a lid 148 which rests upon the upper ends of the several walls of said cabinet and is. hinge-connected to the rear wall 149 by means of hinges 150, which are set in recesses in the top of the wall, as shown in Fig. 7. It will be further noted that a cover member 151 is hinge-connected to the hinged end of the lid 148 by means of binge members 152, as shown in Fig. 7. A further distinction resides in the design of the lattice portion shown in Fig. 5.

In operation, assuming the antenna connected to either of the terminals 22 and 23, the terminal 24 grounded, a source of energy for the several filaments connected to .the terminals 24 and 26, the system is rendered operative upon closing the switch 29. The wave length of the receiving system may now be adjusted to resonance to incoming signal impulses by properly moving the handle 112 of the variometer 14.

While I have described a specific embodiment of my invention, for the purpose of more fully illustrating the objects, advantages and applications thereof, it is apparent that various changes and modificatlons may be made in the circuit arrangement and constructional details without departing member accessible from the top of the lid,

an electron tube, means for so supporting said tube that the same may extend up through said perforation, and a switching chamber, a movable lid for said cabinet, a movable cover for said lid device disposed on saidlid and controlling said electron tube.

comprising a chamber, a-movable lid forsaid cabinet, a movable'cover for said lid enclosing a space therebetween, means for main-' 2. As an article of manufacture, a cabinet tuning device carried on the under side of said hd and having a controllfiif member ach oessible from the top of the an electron tube, means for supporting said tube that the 5 same may extend up through said perforation, a switch in circuit with'said tube disposed on said lid and means carried by said cover for co-operating with said switch in such manner that said switch is actuated into 10 an open position when said cover is closed;

3. A mountin for a tube device comprising, in combination, a base member hav' a serforation large enough to receive said t l be evice, a tube socket device, and means for 15 supporting said tube socket device beneath sa1 perforation.

4. A vacuum tube device comprisin combination, a vacuum-tube device 0 the three electrode type having external circuit- 20 terminal pins therefor, a ballast-lamp device also provided with external circuit terminal pins, a base member having perforations adapted to rec ive said devices, a socket device ada ted to receive all of said terminal 2 pins, an means for su porting said socket device beneath saidlfier orations.

5. In an electri instrument box, a vacuum-blbe device of the three-electrode type aving external circuit-terminal pins therefor, a 'mllast lamp device also provided with external circuit terminal pins, a base member having perforations adapted to receive said de ices, said base member constituting one of the containing walls of said box,-a

socket device ada te to receive all of said terminal pins, an means for resilientl supporting said socket device beneath sai peroratioas. v

6. I1: combination, a cabinet having a control panel constituting one of the con walls thereof, said panel having a rforation large enough to receive a tube evice, a

socket device for said tube, means for an importing said socket device beneath said pc 0- ration and a movable cover for said panel enclosing a space therebetween, said supporting means being such as to cause the ufper end of said tube to extend into said enc osed space.

In testimony whereof, I have hereunto subscribed my name this 28th day of March,

FRANK comm).- 

